Sometimes, the answer to how to win your ex boyfriend back is to make him jealous. There are just some guys who respond to this, after a breakup. This is something that works best with guys who aren't super-inclined to jealousy. If when you were together, he was jealous all the time whenever you were talking to guy friends, then making him jealous now is just going to make him mad. But if he's a guy who is not the overly jealous type, a special effort to get him jealous could be just the trick.
Making him jealous is something that's going to work best with an ex who is aware of you in day-to-day life, at school or on the job. If he doesn't have a way of knowing what you're doing, this technique won't work. He doesn't have to see you in person, but he at least needs to hear about what you're doing from someone else.
Don't be thinking that the only way you can make him jealous is by spending time with another guy. That's not true. There are a lot of things you can make him jealous of.
You can spend time on the internet, and make friends, even with strangers. It's fairly safe if you don't give out personal information. Spend time on Facebook or another social network. Get in touch with people you know, and do some networking. Join forums, and start talking to people who have common interests with you. An online social life is something a guy can be jealous of.
Another thing a guy can be jealous of is the time you spend with your girlfriends. Use your time as a newly single woman to go out in the evenings, to dinner or happy hour. You don't have to try to pick up guys. Just spend time with your friends in the evening, or on the weekends hiking or at a park. Take a road trip with them. As a plus, if you're hot and your friends are hot, he might start fantasizing about all of you being intimate together, and that'll turn him on.
If you do want to make him jealous by spending time with another guy, you can start spending time with an old friend who is male, or with an old boyfriend. Talk about the things you do with the other guy. If you had a previous relationship with the other guy, your ex is all the more likely to get jealous.
If you see your ex at a party, be really sociable. Circulate, and talk to lots of people. Flirt, and make a lot of friends. If he sees other people being attracted to you, he'll be attracted to you too.
If you're shy, and don't have many friends, or go to parties, and the thought of trying to meet new people makes you panic -- then you can try to make your guy jealous by obsessing over a TV or movie character. Pick someone you think is perfect, and talk about his good qualities and how crazy you are about him. This will work best if your ex is also someone who is able to make an emotional connection with fictional characters. If you're lucky, and jealousy brings him back to you, the fact that he knows exactly what kind of guy you're attracted to can be an added benefit.
Bottom line: the main secret to win your ex boyfriend back by making him jealous is to put a lot of energy, and time, into anything that isn't him -- and make sure he knows it.